Study finds solid oxide fuel cells hybrid power system could be ideal for cruise ships

Swiss researchers have developed an always-on fuel cell hybrid power system.

Researchers at the École Polytechnique Fédérale de Lausanne (EPFL), Switzerland, have developed a project that involves a hybrid power system that is centered on solid oxide fuel cells (SOFCs) running on continual load. Through their study, the researchers have found that such an innovative hybrid power system has the potential to benefit cruise ships.

The new system would suit cruise ships due to these ships having diverse power demands.

EPFL researcher Francesco Baldi said that the hybrid power system would be suitable for cruise ships due to the diverse power demands these ships require compared to merchant vessels, which typically require mainly propulsive power.

Solid oxide fuel cells are capable of running on a large variety of gas and liquid fuels, while proton-exchange membrane fuel cells (PEMFCs) rely on hydrogen fuel. Compared to SOFCs, therefore, PEMFCs need vast storage space onboard the vessel if hydrogen fuel is to be used as the primary power source.

Additionally, the researchers’ proposed hybrid storage solution would make it possible to lower the investment cost of the system, while still maintaining the use of the SOFCs as the system’s main energy source.

The solid oxide fuel cells developed by EPFL have achieved 75% efficiency.

The SOFCs developed by the researchers have successfully reached 75% efficiency compared to just over 50% for the most efficient engines. This is impressive, but it should be noted that it can take up to 20 hours for these SOFCs to reach full capacity.

That being said, these SOFCs can be used to produce a combination of electricity, hydrogen-rich synthesis gas, and high-temperature heat. The heat is part of the purifying process to generate hydrogen. The only by products from the process would be carbon dioxide and water.

More specifically, the proposed solid oxide fuel cells hybrid power system that runs at constant load would be coupled with a PEMFC, a battery, and a hydrogen storage tank. The batteries store any excess electricity that is produced when energy demand is lower than the SOFC output. Meanwhile, the syngas that is produced by the cells would be processed to hydrogen that could power auxiliary PEMFCs at peak power demand.

In addition to cruise ships, in their paper the researchers state: “The advantages of the proposed system, particularly in terms of investment cost and weight, would also prove beneficial in other applications related to the transport sector, such as cars, trucks, and airplanes, where the system’s weight constitutes a significant constraint for the design of the power plant.”